AP Biology is an introductory, college-level biology course organized by four Big Ideas, 7 Science Practices, and Student-Directed Lab Investigations. Evolution, Big Idea #1: The process of evolution drives the diversity and unity of life. Cellular Processes: Energy and Communication, Big Idea #2: Biological systems utilize free energy and molecular building blocks to grow, reproduce and to maintain dynamic homeostasis. Genetics and Information Transfer, Big Idea #3: Living systems store, retrieve, transmit and respond to information essential to life processes. Interactions, Big Idea #4: Biological systems interact, and these systems and their interactions possess complex properties. The lab investigations are integrated throughout the course and connect the Big Ideas one to another.